In recent years, systems called home energy management system (HEMS) which perform energy management of housing have been provided for electricity users of general households. The HEMS is a system that utilizes sensors or information technologies. According to the HEMS, electricity use conditions in each household can be ascertained and visualized. As a result, power saving and a reduction in electricity charges are promoted, and thus energy saving effects are expected to be obtained. Such efforts have expanded and started to be applied to areas such as office floors, buildings, and stores.
Technologies for ascertaining operation states of individual electrical devices in households and the like and visualizing such information have been proposed. According to the technologies, it is possible to ascertain individual operation states (types or the like of electrical devices being in operation) of electrical devices at the present point in time in each household and also ascertain use pattern or the like of each electrical device. The related technologies are disclosed in Patent Documents 1 to 4.
Patent Document 1 discloses a technology for ascertaining power consumption of individual electrical devices by including dedicated power consumption measurement devices in the individual electrical devices.
Patent Documents 2 and 3 disclose technologies for presuming operation states of individual electrical devices without directly measuring the power consumption of the individual electrical devices. Specifically, technologies are disclosed in which measurement sensors measuring feature amounts such as power supply currents, power supply voltages, or calculated values such as a statistic obtained from the power supply currents and the power supply voltages are installed in power trunk line portions such as switchboards, and it is presumed which electrical devices are operated using feature amounts (reference information), which are stored in advance, at the time of the operation of electrical devices and measurement results of the measurement sensors.
Patent Document 4 discloses a technology for generating feature amounts (reference information) which are necessary for presuming operation states of the foregoing individual electrical devices. Specifically, a technology is disclosed in which predetermined pieces of data (current consumption or the like) are individually measured by operating the electrical devices one by one in measured housing, and feature amounts are extracted from the pieces of measured data of the respective electrical devices and are preserved.